Hydraulic jacks for tensioning reinforcement elements

ABSTRACT

A hydraulic jack for tensioning reinforcing elements such as wires, rods, bars, cables or the like having a nose member with a longitudinal groove extending from its mouth so that the jack can be placed in position by a lateral movement. A plunger having a longitudinal channel is adapted to slide in the groove of the nose member and the rod to be tensioned is arranged in the channel of the plunger. A number of rams are mounted in the nose member to urge the plunger against biasing return springs towards the mouth to drive home anchor wedges in an anchoring plate for anchoring the rod. A profile member is attached to the nose member. The rod is tensioned by a traction gripper head mounted on a piston rod of a double-acting hydraulic assembly, which is mounted at the end of the profile member opposite the nose member. The profile member has a longitudinal channel which is aligned with the channel of the plunger and the groove of the nose member. One edge of the profile member is turned back to provide a further protection channel for a hydraulic duct for the rams associated with the plunger.

United States Patent 1191 Gomez [451 Sept. 24, 1974 HYDRAULIC JACKS FORTENSIONING REINFORCEMENT ELEMENTS [76] Inventor: Juan Bautista RipollGomez,

Consejo de Ciento, 304, Barcelona, Spain 22 Filed: Sept. 15,1972

21- Appl. No.: 289,450

[30] Foreign Application Priority Data Primary ExaminerOthell M. SimpsonAttorney, Agent, or Firm-Brumbaugh. Graves. Donohue 8; Raymond 57ABSTRACT.

A hydraulic jack for tensioning reinforcing elements such as wires,rods, bars, cables or the like having a nose member with a longitudinalgroove extending from its mouth so that the jack can be placed inposition by a lateral movement. A plunger having a longitudinal channelis adapted to slide in the groove of the nose member and the rod to betensioned is arranged in the channel of the plunger. A number of ramsare mounted in the nose member to urge the plunger against biasingreturn springs towards the mouth to drive home anchor wedges in ananchoring plate for anchoring the rod. A profile member is attached tothe nose member. The rod is tensioned by a traction gripper head mountedon a piston rod of a doubleacting'hydraulic assembly, which is mountedat the end of the profile member opposite the nose member. The profilemember has a longitudinal channel which is aligned with the channel ofthe plunger and the groove of the nose member. One edge of the profilemember is turned back to provide a further protection channel for ahydraulic duct for the rams associated with the plunger.

6 Claims, 5 Drawing Figures BACKGROUND OF THE INVENTION This inventionrelates to a hydraulic jack for tensioning reinforcing elements such aswires, rods, bars, cables or the like for building and otherconstructional purposes.

At the present day, the hydraulic jacks or cylinders employed for thispurpose require an orifice at one of their ends to permit theintroduction of the rods to be tensioned; this, in addition to involvingconsiderable difficulty with regard to the construction of the mechanismas a whole, also causes a considerable loss of operators time during theintroduction of the rods.

On the other hand, it is known that, in present day jacks, the fixing ofthe jaws or clamps and the driving of the machine are conventionallyeffected by complicated mechanisms which, although the desired resultsare in fact achieved, greatly increased the cost of the plant, due tothe complicated form thereof.

The present invention seeks to provide a hydraulic jack which avoidsthese disadvantages.

The invention also seeks to provide a hydraulic jack which has adequatemeans for permitting the lateral introduction of the rods, being at thesame time provided with simple and effective mechanisms for anchoringthe anchor jaws or clamps and for drawing or tensioning the rods.

SUMMARY OF THE INVENTION According to the present invention there isprovided a hydraulic jack for tensioning reinforcing wires, rods, bars,cables or the like, comprising: a nose member having a mouth forabutment against an anchoring plate, which receives anchor wedges foranchoring the reinforcing rod or the like, and having a longitudinalgroove therein extending from said mouth to the other end of said nosemember; a plunger longitudinally slidable in said groove for drivinghome the wedges of said anchoring plate, said plunger having alongitudinal channel therein for receiving an end portion of saidreinforcing rod, said longitudinal groove and said longitudinal channelbeing aligned to permit lateral engagement of said end portion of thereinforcing rod in said channel; flange means on said plunger; hydraulicram means for co-operating with said flange means for urging saidplunger means towards said mouth to drive home the wedges of saidanchoring plate; return biasing means for co-operating with said flangemeans for biasing said plunger away from said mouth; gripping means forgripping said end portion; and traction means for drawing said grippingmeans away from said mouth to tension said reinforcing rod.

In a preferred embodiment of the invention, the grooved nose member isconnected at its end opposite said mouth to a profile member having alongitudinal channel which is aligned with said groove of said nosemember and said channel in said plunger, and said traction meanscomprises a double-acting hydraulic piston and cylinder assembly coupledwith said profile member, a piston rod mounted to said piston extendsinto said channel of the profile member and carries said gripping means.Preferably said gripping means comprises a traction gripper device andsaid profile member has at least one of its edges folded outwardly toconstitute a protective seating for the installation of the ducts of thehydraulic circuit of the machine.

BRIEF DESCRIPTION OF THE DRAWINGS In order that the invention may beclearly understood and readily carried into effect a preferredembodiment thereof will now be described, by way of example only, withreference to the accompanying drawings in which:

FIG. 1 shows a longitudinal section through a hydraulic jack accordingto the invention;

FIG. 2 is a cross sectional view of the jack, taken along the line 2-2of FIG. 1 and looking in the direction of the arrows;

FIG. 3 is a cross sectional view of the jack, taken along the line 3-3of FIG. 1 and looking in the direction of the arrows;

FIG. 4 is a cross sectional view of the jack, taken along the line 44 ofFIG. 1 and looking in the direction of the arrows; and

FIG. 5 is a cross sectional view of the jack, taken along the line 55 ofFIG. 1 and looking in the direction of the arrows.

DESCRIPTION OF AN EXEMPLARY EMBODIMENT Referring to FIG. 1, thehydraulic jack comprises a hollow cylinder 1 and a profile member 2having a longitudinal channel. The cylinder 1 and the profile member 2being interconnected by a member 3, the position of which isintermediate relative to both. A piston rod 4 is adapted to slide withinthe cylinder 1 and in the channel of profile member 2. The front end ofthe piston rod 4, after being introduced into the channel or the profilemember 2, is connected to a traction gripper head 5, this beingconventional drawing gripper means, so that displacement of the pistonrod 4 results also in movement of the traction gripper head 5. Tractiongripper head 5 has gripping means 6 with corresponding wedge-shaped jaws7 urged by spring 7a to grip the rod or bar 8 during tensioning thereof.

The member 3 for connecting the cylinder 1 and profile member 2 operatesas a partition delimiting a pressure chamber 9 formed by it and by apiston 10 connected to the rod 4, whereas a further pressure chamber 11is delimited between the piston 10 and an end face 12 of the cylinder 1;a gasket 13 surrounding the piston 10 completes the hydraulic couplingbetween the piston 10 and the inner wall of cylinder 1. In communicationbetween the pressure chambers 9 and 11 are associated ducts 14 and 15 towhich the appropriate circuit conduits may be connected. With thisarrangement the cylinder 1 and the associated piston 10 comprises adouble-acting hydraulic assembly. The double-acting hydraulic assemblytogether with the piston rod comprise the traction means for drawing thegripping means during tensioning.

At the front end of the profile member 2 there is a nose member 17including a base plate 17a carrying,,at its free fact, a frustoconicalnose portion 17b having a mouth for abutting an anchoring plate 22a,which receives wedges 22 for anchoring the rod 8 after tensioning. Thenose member 17 has a groove 18 extending longitudinally from the mouth17c to the other end thereof and communicates with and includes acentral axis cove 18a thereof. A plunger 19 is slidably positioned inthe portion of the groove 18 whichextends through the nose portion 17band is provided with a longitudinal channel 19a which is aligned withgroove 18 as shown in FIG. 3, so that the bar 8 can be laterallyintroduced into the nose member 17 and plunger 19.

A separate tubular structure 19b (see FIG. 4), which is independent ofthe jack, is threaded on the rod 8 before positioning the jack fortensioning. It is used to anchor wedges 22 in the anchoring plate 22a ashereinafter explained.

At its outer end plunger 19 has a flange on which act two hydraulic rams20 contained in the base plate 17a. Rams 20 are hydraulically actuatedby hydraulic fluid introduced through duct 21 as shown in FIG. 5. Duct21 in turn communicates with the duct connected to the pressure chamber11. In this way, on displacement of the piston rod 4 toward the mouth ofthe jack, for the purpose of releasing the cable 8 after tensioning, thehydraulic rams are actuated to displace the plunger 19 towards the mouthof the jack. The end of the plunger 19 opposite the flange abuts thetubular structure 19b as shown in FIG. 1. The tubular structure 19b isdimensioned to strike the wedges 22 disposed in the anchoring plate 22ato anchor rod 8 when plunger 19 is displaced towards the mouth of thejack. Thus on admitting fluid to the pressure chamber 11 to return thejack to its starting position the wedges 22 are simultaneously drivenhome to anchor the rod 8, since the rams 20 and pressure chamber 11 arefed in parallel.

For withdrawal of the plunger 19, the latter is provided with associatedsprings 23 which on cessation of the pressure exerted by the rams 20,compel the plunger to return to its initial position.

The profile member 2 has an inverted omega shape as shown in FIG. 2. Byhaving its edge portions turned back, profile member 24 provides aprotection channel 25 for duct 21.

From the description given hereinabove it will be appreciated that theuse of the jack concerned permits the achievement of long travel pathsof the bar 8 and also the locking of the wedges 22 with a high degree ofprecision, this being of vital importance with regard to the efficacy ofclamping and the duration thereof, whilst at the same time traction,gripping and withdrawal from the jack are achieved with two single fluidinlets.

While the invention has been particularly shown and described withreference to a preferred embodiment thereof, it will be understood bythose skilled in the art that various changes in form and details may bemade therein without departing from the spirit and scope of theinvention.

I claim:

1. A hydraulic jack for tensioning reinforcing wires, rods, bars, cablesor the like, comprising a nose member having a mouth for abutmentagainst an anchoring plate receiving anchor wedges for anchoring thereinforcing wire, rod, bar, cable or the like, and having a longitudinalgroove therein extending from said mouth to the other end of said nosemember, a plunger longitudinally slidable in said groove for drivinghome the wedges of said anchoring plate, said plunger having alongitudinal channel therein for receiving an end portion of saidreinforcing wire, rod, bar, cable or the like, said longitudinal grooveand said longitudinal channel being aligned to permit lateralintroduction of said end portion in said channel, flange means on saidplunger, hydraulic ram means for co-operating with said flange means forurging said plunger means towards said open mouth to drive home thewedges of said anchoring plate, return biasing means for co-operatingwith said flange means for biasing said plunger away from said mouth,gripping means for gripping said end portion and traction means fordrawing said gripping means away from said mouth to tension saidreinforcing wire, rod, cable or the like.

2. A hydraulic jack according to claim 1, in which the end of said nosemember opposite said mouth is connected to a profile member having alongitudinal channel therein which is aligned with said groove of thenose member and said channel of the plunger, and in which said tractionmeans comprises a double-acting hydraulic assembly coupled with saidprofile member and a piston rod operatively connected to saiddouble-acting hydraulic assembly, the piston rod extending into saidchannel of the profile member and carrying said gripping means.

3. A hydraulic jack according to claim '2, in which said gripping meanscomprises a traction gripper device.

4. A hydraulic jack according to claim 2, in which said profile memberhas an edge portion turnedback to form a further protection channel forat least one hydraulic duct.

5. A hydraulic jack according to claim 4, in which said hydraulic ductis connected to said hydraulic ram means.

6. In a hydraulic jack for tensioning reinforcement elements forbuilding purposes the improvement comprises a nose member having a mouthat one end for abutment against an anchoring plate receiving anchorwedges for anchoring a reinforcement element, a longitudinal groove inthe nose member extending from the mouth to the other end of the nosemember, a plunger slidable in the groove and having a longitudinalchannel therein which is aligned with said groove to permit lateralintroduction of said reinforcement element into said channel, hydraulicrarn means for moving said plunger towards said mouth, to drive home thewedges of the anchoring plate for anchoring said reinforcement element,and return biasing means for biasing said plunger away from said mouth.

1. A hydraulic jack for tensioning reinforcing wires, rods, bars, cablesor the like, comprising a nose member having a mouth for abutmentagainst an anchoring plate receiving anchor wedges for anchoring thereinforcing wire, rod, bar, cable or the like, and having a longitudinalgroove therein extending from said mouth to the other end of said nosemember, a plunger longitudinally slidable in said groove for drivinghome the wedges of said anchoring plate, said plunger having alongitudinal channel therein for receiving an end portion of saidreinforcing wire, rod, bar, cable or the like, said longitudinal grooveand said longitudinal channel being aligned to permit lateralintroduction of said end portion in said channel, flange means on saidplunger, hydraulic ram means for co-operating with said flange means forurging said plunger means towards said open mouth to drive home thewedges of said anchoring plate, return biasing means for co-operatingwith said flange means for biasing said plunger away from said mouth,gripping means for gripping said end portion and traction means fordrawing said gripping means away from said mouth to tension saidreinforcing wire, rod, cable or the like.
 2. A hydraulic jack accordingto claim 1, in which the end of said nose member opposite said mouth isconnected to a profile member having a longitudiNal channel thereinwhich is aligned with said groove of the nose member and said channel ofthe plunger, and in which said traction means comprises a double-actinghydraulic assembly coupled with said profile member and a piston rodoperatively connected to said double-acting hydraulic assembly, thepiston rod extending into said channel of the profile member andcarrying said gripping means.
 3. A hydraulic jack according to claim 2,in which said gripping means comprises a traction gripper device.
 4. Ahydraulic jack according to claim 2, in which said profile member has anedge portion turned back to form a further protection channel for atleast one hydraulic duct.
 5. A hydraulic jack according to claim 4, inwhich said hydraulic duct is connected to said hydraulic ram means. 6.In a hydraulic jack for tensioning reinforcement elements for buildingpurposes the improvement comprises a nose member having a mouth at oneend for abutment against an anchoring plate receiving anchor wedges foranchoring a reinforcement element, a longitudinal groove in the nosemember extending from the mouth to the other end of the nose member, aplunger slidable in the groove and having a longitudinal channel thereinwhich is aligned with said groove to permit lateral introduction of saidreinforcement element into said channel, hydraulic ram means for movingsaid plunger towards said mouth, to drive home the wedges of theanchoring plate for anchoring said reinforcement element, and returnbiasing means for biasing said plunger away from said mouth.